An associative polymer contains pendant groups capable of forming non-specific “associations” with other groups in the polymer or other materials in the medium in which the polymer is present. Generally, the pendant group has both hydrophobic and hydrophilic regions and the associations are generally based on hydrophobic interactions. Hydrogen bonding associations between hydrophilic groups have also been seen under some pH conditions. According to theory, such associations result in thickening by the formation of interpolymer networks above a critical polymer overlap concentration.
Processes for preparing polymers based on alkenes and other copolymerizable ethylenically unsaturated compounds are well known to the skilled worker. The copolymerization takes place essentially in the form of a solution polymerization (see, for example, A. Sen et al., Journal American Chemical Society, 2001, 123, pp. 12738 to 12739; B. Klumperman et al., Macromolecules, 2004, 37, pp. 4406 to 4416; A. Sen et al., Journal of Polymer Science, Part A: Polymer Chemistry, 2004, 42(24), pp. 6175 to 6192; WO 03/042254, WO 03/091297 or EP-A 1384729) or in the form of an aqueous emulsion polymerization, this taking place in particular on the basis of the lowest alkene, ethene (see, for example, U.S. Pat. Nos. 4,921,898, 5,070,134, 5,110,856, and 5,629,370, or EP Patent Nos. EP-A 295727, EP-A 757065, EP-A 1114833 or German Patent No. DE-A 196 20 817).
Prior art relating to free-radically initiated aqueous emulsion polymerization using higher alkenes is as follows. For example, DE-A 1720277 discloses a process for preparing polymer dispersions using vinyl esters and 1-octene. The weight ratio of vinyl ester to 1-octene can be from 99:1 to 70:30. Optionally the vinyl esters can be used to a minor extent in a mixture with other copolymerizable ethylenically unsaturated compounds for the emulsion polymerization.
S. M. Samoilov in J. Macromol. Sci. Chem., 1983, A19(1), pp. 107 to 122 describe the free-radically initiated aqueous emulsion polymerization of propene with different ethylenically unsaturated compounds. The outcome observed there was that the copolymerization of propene with ethylenically unsaturated compounds having strongly electron-withdrawing groups, such as chlorotrifluoroethylene, trifluoroacrylo-nitrile, maleic anhydride or methyl trifluoroacrylate, gave polymers having a markedly higher propene fraction, or copolymers having higher molecular weights, than when using the typical ethylenically unsaturated compounds of free-radically initiated aqueous emulsion polymerization, viz. vinyl acetate, vinyl chloride, methyl acrylate, and butyl acrylate. The reasons given for this behavior include in particular the hydrogen radical transfer reactions that are typical of the higher alkenes.
Additionally, U.S. Pat. No. 7,816,441 discloses the use of low molecular weight addition polymer A with a molecular weight of less than 100,000 Daltons composed in copolymerized form of 0.1 percent to 40 percent by weight of at least one C3 to C30 alkene, 40 percent to 99.9 percent by weight of at least one ethylenically unsaturated C3 to C6 monocarboxylic acid, 0 percent to 50 percent by weight of at least one ethylenically unsaturated C4 to C12 dicarboxylic acid and/or of the ethylenically unsaturated dicarboxylic monoalkyl esters or dicarboxylic anhydrides obtainable from said acid, and 0 percent to 30 percent by weight of at least one other ethylenically unsaturated compound which is copolymerizable with the aforementioned monomers, as a dispersing assistant in free-radically initiated aqueous emulsion or suspension polymerization.
Accordingly, there is an ongoing, unresolved need and desire for polymer compositions having improved rheological and aesthetic properties in an aqueous and surfactant media. The polymer compositions of the present invention are based on utilizing alpha olefins to enhance thickening and rheological properties of the aqueous system.